1,2,3,4,5,8 - hexahydro - 1,5 - methano-benzo(f)(1,4)diazocine and derivatives thereof



United States Patent 3,472,852 1,2,3,4,5,8 I-IEXAHYDRO 1,5 METHANO- BENZO[f][1,4]DIAZOCINE AND DERIVA- TIVES THEREOF Franklyn W. Gubitz, Nassau, N.Y., assignor to Sterling Drug Inc., New York, N.Y., a corporation of Delaware No Drawing. Filed May 28, 1965, Ser. No. 459,884 Int. Cl. C07d 53/00 US. Cl. 260-268 6 Claims ABSTRACT OF THE DISCLOSURE 1,2,3,4,5,8 hexahydro 4 substituted 1,5 methanobenzo [f] [1,4] diazocines and 1,2,3,4,5,6-heXahydro-4-sub stiuted 1,5-methanobenzo[g] [1,4]-diazocines, useful as analgesic antagonists, are prepared by reducing the corresponding 3-oxo compounds unsubstituted in the 4-position, and N-alkylating the 4-position. Said 3-oxo compounds are in turn prepared by pyrolitic cyclization of 4-an1ino-2- carbalkoxymethyl 1,2,3,4 tetrahydroisoquinolines and S-amino-l-carbalkoxymethyl-1,2,3,4-tetrahydroquinolines.

having the structural formulas Formula I Formula II and in which R is a member of the group consisting of: hydrogen; lower alkyl; lower-alkenyl; cyclopropyl; and benzyl.

When the group R is lower alkyl there are included the monovalent radicals of relatively low molecular weight derived from saturated branched and unbranched aliphatic hydrocarbons; the preferred alkyl radicals have 1-5 carbon atoms as illustrated by, but not limited to, methyl, ethyl, isopropyl, n-butyl, pentyl. When R is lower alkenyl, there are included the monovalent lower molecular weight unsaturated aliphatic hydrocarbon radicals containing a double bond, and preferably having 2-5 carbon atoms, as illustrated by, but not limited to,

CH=CH -CH CHCH CH CH=CH CH=C(CH CH:CHCH CH CH CH CH==CHCH CH and the like. The new 1,2, 3,4,5 ,8-hexahydro-4-(R-CH 1,5 -methanbenzo [f] [1,4] diazocines and 1,2, 3,4,5 ,6-hexahydro-4- (RCH 1 ,5 -methanobenzo- [g] [1,4] diazocines are conveniently prepared by N-alkylating the corresponding secondary amines, namely 1,2,3,4,5,8-hexahydro-1,5-methanobenzo[f] [l,4]diazocine and l,2,3,4,5,6-hexahydro-l,S-rnethanobenzo [g] 1,4]diazocine,

by heating with an alkylating agent having the formula RCH An, where R has the same meaning indicated hereinabove and An is the anion of a strong organic or inorganic acid, for instance a reactive halide or an arylsulfonate, e.g., a tosylate in the presence of an acidabsorbing medium for instance an alkali metal carbonate or hydroxide, for instance sodium hydroxide. This alkylation reaction is preferably carried out in the presence of a suitable reaction medium such as an N,N-(di-lower alkyl)-lower alkanamide, for instance N,N-dimethylformamide or N,N-dimethylacetamide or a lower alkanol, for instance methanol or ethanol.

Another method suitable for preparing the new compounds of the invention comprises N-acylating the 1,2,3,4,5,8-heXahydro-1,5-methanobenzo[f] [1,4] diazocine or 1,2,3,4,5,6-hexahydro-l ,5-methanobenzo[ g] [1,4] diazocine with an acid halide or acid anhydride of an acid having the formula RCOOH and reducing the resulting i Q NH Formula III and Formula IV respectively, with a reducing agent effective to reduce the carbonyl of the amide to -CH for instance lithium aluminum hydride or equivalent thereof.

The novel cyclic amides of Formulas III and IV are also within the purview of the invention and are preferably prepared by heating at from 180 C. to 200 C. novel 4-amino-2-carbalkoxymethyl-1,2,3,4-!tetrahydroisoquinolines (V) and 3-amino-l-carbalkoxymethyl-1,2,3,4- tetrahydroquinolines (VI) respectively, to ring close with the elimination of an alkanol.

Compounds V and VI are prepared from 4-arninoisoquinoline and 3-aminoquinoline by the following sequence of reactions wherein the preparation of V is illustrated but which applies as well to the preparation of VI from S-aminoquinoline:

In the above flow sheet the amino group 'of 4-aminoisoquinoline is blocked by any group conventionally used to protect amino groups, for instance lower alkanoyl to give for example 4-formamidoisoquinoline or as illustrated carbobenzoxy. The carbobenzoxyamino compound is quaternized with an alkyl haloacetate to give the appropriate isoquinolinium compound which is reduced over platinum oxide to the 1,2,3,4-tetrahydro compound. The protective grouping is then removed by reduction over a palladium on charcoal catalyst or by other procedures known to those skilled in the art, to give the desired amino compound V.

The acid-addition salts of the bases herein described are the form in which the bases are most conveniently prepared for use and are the full equivalents of the subject matter specifically claimed. The acid moieties or anions in these salt forms are in themselves neither novel nor critical and therefor can be any acid anion or acidlike substance capable of salt formation with the free base form of the compounds. The preferred type of salts are water-soluble pharmacologically acceptable salts, that is, salts whose anions are relatively innocuous to the animal organisms in pharmacological doses of the salts, so that the beneficial physiological properties inherent in the free base are not vitiated by side efiects ascribable to the anions; in other words, the latter do not substantially affect the pharmacological properties inherent in the cations. In practising the invention, it has been found convenient to form the hydrochloride or nitrate salt. However, other appropriate pharmacologically acceptable salts within the scope of the invention are those derived from mineral acids such as hydrobromic acid, hydriodic acid, nitric acid, phosphoric acid, sulfamic acid and sulfuric acid; and organic acids such as acetic acid, citric acid, tartaric acid, lactic acid, methanesulfonic acid, ethanesulfonic acid, quinic acid, and the like, giving the hydrobromide, hydriodide, nitrate, phosphate, sulfamate, sulfate, acetate, citrate, tartrate, lactate, methanesulfonate, ethanesulfonate and quinate respectively.

Although pharmacologically acceptable salts are preferred, those having toxic anions are also useful. All acidaddition salts are useful intermediates as sources of the free base form even if the particular salt per se is not desired as the final product, as for example when the salt is formed only for purposes of purification or identification, or when it is used as an intermediate in preparing a pharmacologically acceptable salt by ion exchange procedures.

The structures of the compounds of this invention followed from the methods of synthesis which were used and from the elementary analyses of the products obtained.

The invention is illustrated by the following examples without, however, being limited thereto.

EXAMPLE 1 1,2,3,4,5,6-hexahydro-4-methyl-1,5-methanobenzo[g] [1,4]-diazocine A mixture of 16.1 g. of 1,2,3,4,5,6-hexahydro-1,5- methanobenzo[g][1,4]diazocine and 50 ml. of formic acid was cooled to 27 C. and 30 ml. of 35-40% formaldehyde added dropwise. After the temperature rose spontaneously to 58 C. the mixture was heated to 8590 C. for one hour with stirring. The excess reactants were removed by distillation, the residual oil treated with sodium hydroxide solution and the mixture triturated with ether. The ether extracts were dried and the ether removed by evaporation to give a yellow oil. Distillation of the oil under diminished pressure gave 8.7 g'. of 1,2,3,4,5,6 hexahydro-4-methyl 1,5-methanobenzo [g][1,4]diazocine, B.P. 129-131 C./8 mm. and having the molecular formula C H N The free base was treated with 12 ml. of 2 N nitric acid and the mixture taken up in an ethanol-benzene solution and cooled. The crystals thus obtained were collected by filtration, recrystallized from methanol and dried in vacuo. There was thus obtained 11 g. of the nitrate salt of 1,2,3,4,5,6-

hexahydro 4-methyl 1,5 methanobenzo[g][l,4]diazocine, M.P. 120-121 C.

EXAMPLE 2 1,2,3,4,5,8-hexahydro-4-methyl-1,5-methanobenzo [f] [1,4] diazocine Following a procedure similar to that described in Example 1 hereinabove, 17.4 g. of l,2,3,4,5,8-hexahydro- 1,5-methanobenzo[g] [1,4]diazocine was alkylated with 50 ml. of formic acid and 30 ml. of 37% formaldehyde to yield 14 g. of 1,2,3,4,5,8-hexahydro-4-methyl-1,5- methanobenzgo[f] [1,4]diazocine, having the molecular fOrmula C H N This base was converted to its hydro chloride, a white crystalline powder which weighed 16.6 g. and melted at 283-285 C. (dec.).

EXAMPLE 3 1,2,3,4,5,6-hexahydro-4-allyl-1,5-methanobenzo [f] [1,4] diazocine A mixture of 8.7 g. of 1,2,3,4,5,8-hexahydro-1,5-methanobenzo[f] [1,4]diazocine and 6.1 g. of allyl bromide in 125 ml. of dimethylformamide was refluxed overnight. The solvent was removed by vacuum distillation and the residue taken up in sodium hydroxide solution and the mixture extracted with ether. The ether extracts were 0 melted at 231-234 C. and to its dinitrate salt, a white solid which melted at 162-164" C.

EXAMPLE 4 1,2,3,4,5,6-hexahydro-4-allyl-l,S-methanobe'nzo[ g] [1,4] diazocine Following a procedure similar to that described in Example 3, 3.5 g. of 1,2,3,4,5,6-hexahydro-1,5-methanobenzo[g][1,4]diazocine was N-alkylated with 2.4 g. of-

allyl bromide to yield l,2,3,4,5,6,-hexahydro-4-al1yl-1,5-

methanobenzo[g][1,4]diazocine, having the molecular formula C H N This base was converted to its dihydrochloride, colorless prisms which melted at 239 C. (dec.).

EXAMPLE 5 1,2,3,4,5,8-hexahydro-4-cyclopropylmethyl- 1,5-methanobenzo[f] [1,4]diazocine (A) A solution of 3.5 g. of 1,2,3,4,5,'8-hexahydro-1,5- methanobenzo[f] [1,4]diazocine in an ether-alcohol mixture was treated with an excess of cyclopropanecarboxylic acid chloride and the mixture refluxed for several hours. The excess acid chloride was removed by distillation and the solid which separated was collected by filtration then dissolved in water. The aqueous solution was treated with a saturated potassium carbonate solution and extracted with chloroform. The chloroform extracts were dried, the chloroform removed and the residue left standing at room temperature. The crystals which precipitated were collected, recrystallized from ether-acetone to give 1,2,3,4,5,8hexahydro-4-cyclopropanecarbonyl-1,5- methanobenzo[f] [1,4]diazocine, having the molecular formula C H N O and melting at 97-103" C.

(B) The amide from A (2.4 g.) was reduced by heating to reflux with 1.1 g. of lithium aluminum hydride in 50 ml. of tetrahydrofuran. The hydride complex was decomposed with 3 ml. of water and the mixture filtered. The colorless filtrate was evaporated on a steam bath to yield a pale yellow oil which was l,2,3,4,5,8-hexahydro- 4-cyclopropy1methyl- 1,5 methanobenzo [f] 1,4] diazocine, having the molecular formula C H N This base was converted to its dihydrochloride salt, a white solid which, after recrystallization from methanol, melted at 267-268 C. (dec.). 1

EXAMPLE 6 1,2,3,4,5,8-hexahydro-4-phenylethyl-1,5- methanobenzo [f] 1,4] diazocine (A) A mixture of 7 g. of 1,2,3,4,5,'8-hexahydro-1,5- methanobenzo[f][1,41diazocine and 6.75 g. of phenylacetyl chloride in 30 ml. of sodium hydroxide was shaken vigorously then allowed to cool. The oil which separated was extracted with ether, the ether extracts dried and the ether removed by evaporation. There was thus obtained 1,2,3,4,5,8-hexahydro 4 phenylacetyl-1,5- methanobenzo[f] [1,4]diazocine.

(B) The amide from part A was reduced with lithium aluminum hydride following a procedure similar to that described in Example SE to give the free base 1,2,3,4,5,8- hexahydro-4-phenylethyl 1,5 methanobenzo[f] [1,4]diazocine, having the molecular formula C H N This base was converted to its dihydrochloride, awhite powder which melted at 239-245" C.

The following are further illustrative examples of the compounds of Formulas I and II which are obtained by proceeding in accordance with the methods hereinabove described:

1,2,3,4,5,6-hexahydro-4-cyclopropylmethyl- 1,5-methanobenzo[ g] [1,4] diazocine; 1,2,3,4,5,8-hexahydro-4-pentyl-1,5-methanobenzo [f] [1,4] diazocine; 1,2,3,4,5 ,8-hexahydro-4-dimethylally1-1,5-methanobenzo [f] [1,4] diazocine; 1,2,3 ,4,5 6-hexahydro-4-phenylethyl- 1,5 -methanobenzo[ g] [1,4] diazocine; 1,2, 3 ,4, 5 ,6-hexahydro-4-dimethylallyl- 1,5methanobenzo[g] [1,4]diazocine; 1,2,3,4,5,6-hexahydro-4-pentyl-1,5-methanobenzo [g] [1,4]diazocine; 1,2,3 ,4,5 8 -hexahydro-4-hexenyll ,S-methanobenzo[f] [1,4]diazocine; 1,2,3,4,5,8-hexahydro-4-sec. butyl-1,5-methanobenzo [f] [1,4] diazocine; 1,2,3,4,5,8-hexahydro-4-( 3-methyl-2-butenyl) 1,5-methanobenzo [f1 [1,41diazocine;

6 1,2,3,4,5,6-hexahydro-4- 3-methyl-2-butenyl) 1,5-methanobenzo[ g] [1,4] diazocine; 1,2,3,4,5,6-hexahydro-4-(3-methylbutyl)-1,5-

methanobenzo [g] [1,4] diazocine.

Compounds of Formulas I and II hereinabove which were prepared as described in the foregoing examples were found to be antagonists of certain strong analgesics. Thus, when tested in rats by a modified DAmour-Smith test procedure and in dogs, they were found to be antagonists of the analgesic activity of morphine and meperidine. In this test procedure, when the compounds of this invention were administered prior to or simultaneously with administration of morphine 0r meperidine, the expected analgesic effect of the latter was decreased with increasing dosage levels of the former to a point where no analgesic effect was obtained. And when the new compounds were administered after the administration of morphine or meperidine, the analgesic effect was diminished or terminated, depending on the dosage levels involved. For example representative compounds of this invention, each in the form of an aqueous solution of an acid-addition salt, were administered subcutaneously to rats to determine the dosage level in terms of weight of antagonist per kilogram of body weight of the animal, which caused reduction of the analgesic effect of a 60 mg./kg. dose of meperidine hydrochloride by approximately 50 percent, so that the analgesic effect produced by the combination of the antagonist and the meperidine hydrochloride was substantially the same as the analgesic effect produced by a 30 mg./kg. dose of meperidinehydrochloride alone. Thus results thus obtained for each of the indicated compounds were as follows: 1,2,3,4,5,8- hexahydro 4 allyl 1,5 methanobenzo[f] [1,4]diazocine, 28 mg./kg.; 1,2,3,4,5,8-hexahydro-4-phenylethyl- 1,5-methanobenzo[f] [l,4]diazocir1e, 10 mg./kg.; and 1,2,3,4,5,6 hexahydro 4 allyl 1,5 methanobenzo [g] [1,4]diazocine, 25 mg./kg.

In addition to having antagonistic activity toward morphine and meperidine 1,2,3,4,5,8 hexahydro 4 allyl 1,5 methanobenzo[f] [1,4]diazocine and 1,2,3,4,5,8- hexahydro 4 phenylethyl 1,5 methanobenzo[f] [1,4]diazocine were found to have psychomotor depressant properties, an activity found in l,2,3,4,5,6-hexahydro- 4 methyl 1,5 methanobenzo[g][1,4]diazocine, 1,2, 3,4,5,8 hexahydro 1,5 methanobenzo[f][1,4]diazocine, and 1,2,3,4,5,8 hexahydro 4 cyclopropylmethyl- 1,5-methanobenzo[f] [1,4]diazocine.

INTERMEDIATES 18.4 g. of ethyl bromoacetate in 50 ml. of ethanol was heated on a steam bath until all the solvent had evaporated. The solid which separated was collected by filtration and dried to give 3-acetamido-l-carbethoxymethylquinolinium bromide, having the melting point ZOO-201 C. (dec.).

A solution of 149 g. of 3-acetamido-l-carbethoxymethylquinolinium bromide in 1,600 ml. of methanol-was hydrogenated over platinum oxide at an initial pressure of 150 p.s.i. The catalyst was removed by filtration and the solvent removed by vacuum distillation. The residue was made basic with saturated potassium carbonate and extracted with chloroform. The chloroform extracts were dried, the chloroform evaporated and the residue distilled to give a viscous liquid, B.P. 216-220 C./0.2 mm., which solidified upon standing. The solid was recrystallized several times from ethyl acetate to give 3-acetamido- 1 carbethoxymethyl 1,2,3,4 tetrahydroquinoline, M.P. 109-112 C.

Dry hydrogen chloride gas was bubbled into a solution of 31 g. of 3-acetamido-1-carbethoxymethyl-1,2,3,4-tetrahydroquinoline in 300 ml. of methanol and the mixture refluxed for three hours then cooled. The solid which separated was removed by filtration and the filtrate made basic with saturated potassium carbonate solution then extracted with chloroform. The chloroform was removed by evaporation and the residue distilled to give 3-amino- 7 carbethoxymethyl 1,2,3,4 tetrahydroquinoline, B.P. 125 C./0.09 mm. and having the molecular formula C H N O The base was converted to the acetate salt, a white solid melting at 103 C.

3 amino 1 carbethoxymethyl 1,2,3,4 tetrahydroquinoline was also prepared as follows: To a solution of 14.4 g. of 3-aminoquinoline in 150 ml. of pyridine was added with cooling 18 g. of carbobenzoxy chloride and the mixture stirred for one hour. The reaction mixture was poured into one liter of water and the solid which separated collected by filtration. This product, after recrystallization from isopropanol, melted at 199201 C. and was 3-carbobenzoxyaminoquinoline, having the molecular formula C H N This compound (2.8 g.) was refluxed for two hours with 1.8 g. of ethyl bromoacetate in 50 ml. of anhydrous ethanol. Addition of dry ethyl ether caused the precipitation of a solid which was collected by filtration and dried. The 3-carbobenzoxyamino 1 carbethoxymethylquinolinium bromide thus obtained had a melting point of 166-170 C. (dec.) and the molecular formula C H BrN O Reduction of 8.9 g. of this quaternary in 300 ml. of methanol over a platinum oxide catalyst followed by removal of the catalyst and evaporation of the solvent gave a pink solid which after three recrystallizations from ethanol gave white needles of 3-carbobenzoxyamino-l-carbethoxymethyl-1,2, 3,4-tetrahydroquinoline, M.P. 111-114 C.

A solution of 48.7 g. of 3-carbobenzoxyamino-l-carbethoxymethyl 1,2,3,4 tetrahydroquinoline in 1,600 ml. of ethanol was reduced over a palladium on charcoal catalyst. The catalyst was removed, the solvent evaporated and the residue basified with potassium carbonate solution. Extraction with chloroform followed by removal of the chloroform gave an oil which was the free base 3- amino-l-carbethoxymethyl-l,2,3,4tetrahydroquinoline.

A mixture of 18.8 g. of 3-amino-1-carbethoxymethyl- 1,2,3,4-tetrahydroquinoline and 500 ml. of Carbitol was heated to about 180 C. and the mixture refluxed overnight. The Carbitol was removed by vacuum distillation and the residue taken up in either. The amide product, 1,2,5,6 tetrahydro 3 oxo 1,5 methanobenzo[g] [1,4]diazocine, which separated melted at 202-203 C. and had the molecular formula C H N O. The base was converted to its hydrochloride salt which crystallized as white prisms melting at 268272 C. (dec.).

To a cooled suspension of 17 g. of lithium aluminum hydride and 20 g. of aluminum chloride in 1,000 ml. of tetrahydrofuran was added 21.1 g. of the above-mentioned amide in 1000 ml. of tetrahydrofuran and the mixture refluxed overnight. The metal complex was decomposed by the addition of 67 ml. of water and the solvent removed by distillation. The residual oil was distilled to give 16.1 g. of l,2,3,4,5,6-hexahydro-1,5-methanobenzo- [g] [1,4]diazocine having the molecular formula and the boiling point 6571 C./.U4 mm.

(B) Following a procedure similar to that described hereinabove for the preparation of 3-carbobenzoxyaminoquinoline, 97.5 g. of 4-aminoisoquinoline and 117 g. of carbobenzoxy chloride in one liter of pyridine yielded 35 g. of 4-carbobenzoxyaminoisoquinoline having the moreoular formula C H N O and melting at 139-140 C.

Quaternization of this product with ethyl bromoacetate using a procedure similar to that described hereinabove for the preparation of 3 carbobenzoxyamino-l-carbethoxymethylquinolinium bromide gave, from 17.6 g., 7.4 g. of 2 carbethoxymethyl 4-carbobenzoxyaminoisoquinolinium bromide having the molecular formula and the melting point 111-112 C. (dec.).

Reduction of this quaternary using a procedure similar to that described hereinabove for the corresponding quinoline compound there was obtained 4-amino-2-carbethoxymethyl-l,2,3,4-tetrahydroisoquinoline which was converted to its dihydrochloride salt, melting point 167-171 C. (dec.).

The free base 4 amino-2-carbethoxymethyl-1,2,31,4- tetrahydroisoquinoline was heated to 180 C. at which point ethanol was liberated. The reaction mixture was cooled and allowed to stand. The solid which separated was collected by filtration and recrystallized from acetonitrile to yield 1,2,7,8-tetrahydro-3-oxo-1,S-methanobenzo [f][1,4]-diazocine, having the molecular formula n n z and which melted at 165-167 C. This amide was converted to its hydrochloride salt which melted at 275- 276 C.

The above amide (149 g.) was reduced with g. of lithium aluminum hydride and 106 g. of aluminum chlo ride in eight liters of tetrahydrofuran using a procedure similar to that described above in (A). There was thus obtained 128 g. of 1,2,3,4,5,8 hexahydro-1,5-methanobenzo[f] [1,4]diazocine having the molecular formula C I-I N and which boiled at 163-173 C./l3 mm. This free base was converted to its dihydrochloride salt which melted above 300 C.

I claim:

1. 1,2,3,4,5,8 hexahydro-4-(R-CH --)-l,5-methanobenzo[f][l,4]diazocine wherein R is a member of the group consisting of hydrogen, lower alkyl, lower alkenyl, cyclopropyl and benzyl.

2. 1,2,3,4,5,8 hexahydro-4-(RCH )-1,5-methanobenzo[f][l,4]diazocine, wherein R is lower alkyl.

3. 1,2,3,4,5,8 hexahydro-4-(RCH -)-1,5-methanobenzo[f][l,4]diazocine, wherein R is lower alkenyl.

4. 1,2,3,4,5,8 hexahydro 4-methy1-1,5-methanobenzo [f] [1,4]diazocine.

5. 1,2,3,4,5,8 hexahydro 4-allyl-1,5-methanobenzo [f] [1,4]diazocine.

6. 1,2,3,4,5,8 hexahydro 4 cyclopropymethyl-l,5- methanobenzo [f] [1,4] diazocine.

US. 01. X.R.

53 233 UNITED STATES P1 TENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, +72,852 Dated October M 1969 Inve t y Franklyn W. Gubitz It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 19, "pyrolitic" should read --pyrolytic--. Column 2, line 9, "-methanbenzo' should read -methanobenzo- Column 4, line 45, "methanobenzgo" should read -methanobenzo-.

Column 7, line 7, "7-carbethoxymeth 1-" should read --l-carbethoxymethy1- line 46, 'either" should read -ether--.

SIGNED AND SEMEB AUG181970 (SEAL) Athest:

I Q: commissioner of Patents 

